Recover the complicated situation after my bad merge

I made a mistake merge.  Reverting it in c778945806 undid the state
on master, but now I realize it crippled the git merge mechanism.
As the merge contained a mix of commits from `master..staging-next`
and other commits from `staging-next..staging`, it got the
`staging-next` branch into a state that was difficult to recover.

I reconstructed the "desired" state of staging-next tree by:
 - checking out the last commit of the problematic range: 4effe769e2
 - `git rebase -i --preserve-merges a8a018ddc0` - dropping the mistaken
   merge commit and its revert from that range (while keeping
   reapplication from 4effe769e2)
 - merging the last unaffected staging-next commit (803ca85c20)
 - fortunately no other commits have been pushed to staging-next yet
 - applying a diff on staging-next to get it into that state

pkgs/development/libraries/mesa/missing-includes.patch

@@ -9,18 +9,6 @@
  #include "pipe/p_compiler.h"
  #include "pipe/p_state.h"
  
---- ./src/util/rand_xor.c.orig	2017-06-20 00:38:57.199474067 +0200
-+++ ./src/util/rand_xor.c	2017-06-20 00:40:31.351279557 +0200
-@@ -23,7 +23,9 @@
-  */
- 
- #if defined(__linux__)
-+#include <sys/types.h>
- #include <sys/file.h>
-+#include <sys/stat.h>
- #include <unistd.h>
- #include <fcntl.h>
- #else
 --- ./src/amd/vulkan/winsys/amdgpu/radv_amdgpu_winsys.h
 +++ ./src/amd/vulkan/winsys/amdgpu/radv_amdgpu_winsys.h
 @@ -28,6 +28,8 @@